1. Field of the Invention
The invention relates to a toothed transfer wheel for components such as preforms or receptacles each component having a ring or neck fitted with a flange.
2. Description of Background and Relevent Information
In order to manufacture bottles or flasks or more generally receptacles made of a thermoplastic material, it is known to use preforms obtained, for example, by injection and which are in the form of a tubular body, closed at one end while its other open end is provided with a ring or neck generally fitted with a flange.
The bodies of the preforms must be subjected to a thermal treatment before being expanded during a moulding operation by blowing or steam blowing.
In a manufacturing line of this type, the preforms and/or the receptacles obtained by blowing circulate from one manufacturing station to another and even within certain stations themselves such as, for example, a thermal oven for preforms.
In order to transport the preforms and/or the receptacles, it is known to hold them up and to guide them on rails on which they are supported by their flanges.
In certain cases, it is necessary to use ring and pinion gearing, for example, to pass preforms from a supply station provided with an inclined rail to the heat treatment oven and it is then known to use a toothed transfer wheel, where the preforms are held up by their flanges, during rotation of the wheel, between respectively arrival and discharge areas or stations provided close to the periphery of the wheel.
The toothed wheel is formed as a single component and in certain cases it can happen that a preform or a receptacle gets jammed between the leading face of a tooth and the guide rail, causing locking of the wheel and because of that, jamming of the other devices driven by the same motor (a single motor is generally used for the different devices because of problems of synchronisation), such as, for example, the system for moving the preforms forward into the heat treatment oven, which clearly causes preforms which have spent too long in the oven to be lost and a loss of the time spent restoring the operation.
Even if several independent motors are used to prevent loss at a station located downstream in the manufacturing line, in addition to the problem of the extra cost and all the difficulties of synchronisation and the subsequent resetting of the motors, the jamming of the transfer wheel still remains very troublesome.